Question

我目前正在使用BigDecimal，这是我获取2个精度数字的实现之一：

    mDbHelper.open();
    BigDecimal total = mDbHelper
            .getTotal(Type.Income, "20130101 12:00:00", "20131231 12:00:00");
    BigDecimal expense = mDbHelper.getTotal(Type.Expense, "20130101 12:00:00",
            "20131231 12:00:00");
    BigDecimal saving = mDbHelper.getSaving("feb");
    mDbHelper.close();
    BigDecimal remaining = total.subtract(expense.add(saving));

    Log.d("total get", total.toPlainString());
    Log.d("expense get", expense.toPlainString());
    Log.d("saving get", saving.toPlainString());
    Log.d("remaining get", remaining.toPlainString());

    try {
        percentRemain = (double) Math.round(remaining.multiply(new BigDecimal(10000.0))
                .divide(total, BigDecimal.ROUND_HALF_UP).doubleValue()) / 100;
        Log.d("percentRemain", "" + percentRemain);
        percentExpense = (double) Math.round(expense.multiply(new BigDecimal(10000.0))
                .divide(total, BigDecimal.ROUND_HALF_UP).doubleValue()) / 100;
        Log.d("percentExpense", "" + percentExpense);
        Log.d("before calculation saving =", saving.toPlainString());
        Log.d("before calculation total =", total.toPlainString());
        percentSaving = ((double) Math.round(saving.multiply(new BigDecimal(10000.0))
                .divide(total, BigDecimal.ROUND_HALF_UP).doubleValue())) / 100d;
        Log.d("percentSaving", "" + percentSaving);

        Log.d("multiply", "" + saving.multiply(new BigDecimal(10000.0)).doubleValue());

        Log.d("divide",
                ""
                        + saving.multiply(new BigDecimal(10000.0))
                                .divide(total, BigDecimal.ROUND_HALF_UP).doubleValue());

    } catch (ArithmeticException e) {
        e.printStackTrace();
        percentRemain = 0.0f;
        percentExpense = 0.0f;
        percentSaving = 0.0f;
    }

percentSaving == 0.0

时，我不知道为什么saving >= 10,000,000

任何观点？请指导我。

这是我记录的变量值：

02-28 16:55:12.250: D/total get(29448): 41623000
02-28 16:55:12.250: D/expense get(29448): 7186545.0
02-28 16:55:12.250: D/saving get(29448): 10000000
02-28 16:55:12.250: D/remaining get(29448): 24436455.0
02-28 16:55:12.250: D/percentRemain(29448): 58.71
02-28 16:55:12.250: D/percentExpense(29448): 17.27
02-28 16:55:12.250: D/before calculation saving =(29448): 10000000
02-28 16:55:12.250: D/before calculation total =(29448): 41623000
02-28 16:55:12.250: D/percentSaving(29448): 0.0
02-28 16:55:12.250: D/multiply(29448): 1.0E11
02-28 16:55:12.250: D/divide(29448): 0.0

percentExpense与percentSaving

具有相同的公式

添加了我的方法和日志。抱歉这个烂摊子。

解决方案

我已将公式更改为此，现在看起来它返回了正确的值。

percentExpense = (double) Math.round(expense.multiply(new BigDecimal(10000.0))
                .divide(total, 4, BigDecimal.ROUND_HALF_UP).doubleValue()) / 100;

操作BigDecimal会产生意外结果

0 个答案: